A proposed $5bn transmission line connecting wind farms off the East coast of the US to the mainland is on track to come online by 2017, after the Google-backed project cleared another regulatory hurdle.

The Department of the Interior said on Monday there was "no overlapping competitive interest" in the areas earmarked for building the line (see map), which clears the way for an environmental review.

However, the review of impacts on fishing, marine life and other factors could take up to two years to complete - a scenario familiar to offshore wind farm developers who have been dogged by slow progress securing planning permissions. The $1bn Cape Wind project off the Nantucket Sound, the first major offshore wind project in the US, has suffered almost a decade of delays mainly brought about by legal challenges from local residents.

The Atlantic Wind Connection line is intended to transmit up to 6GW of electricity from yet to be constructed offshore wind farms along two, 250 mile long parallel lines, strengthening the ageing electricity network along the East Coast in the process.

Interior officials said the government hopes to start selling leases to wind farm developers in the coming months, although they could not say when offshore wind farms would start producing power for the region.

"The governors up and down the East Coast are extraordinarily interested in broadening out their energy portfolio with offshore wind," Tommy Beaudreau, the chief of Interior's Bureau of Ocean Energy Management, told reporters in a teleconference. "We have seen a level of engagement and interest by the governors ... in getting steel in the water."

In related news, Scottish First Minister Alex Salmond has welcomed progress on a proposed interconnector between Scotland-Norway joining the UK and Scandinavian electricity grids.

After securing grants of €50,000 from the Scottish European Green Energy Centre, which followed a €690,000 EU grant in March, work has now started on a cable route study while environmental assessments in the UK and Norway are also under way.

"From world-leading offshore wind, marine and hydro energy in the north of Europe, to massive solar power in the south, we have huge natural renewable resources, which must be harnessed in the most efficient way to deliver benefits for all the continent's citizens," Salmond told a conference in Norway yesterday.

"The NorthConnect project is an excellent example of the kind of grid interconnection that will be needed across the continent to ensure we maximise the contribution of all European nations to reduce our reliance on imported fossil fuels, increase energy security and meet targets for reduced greenhouse gas emissions and renewable energy generation."